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What Train of Thought | John McAleely talks about

Posts tagged with 'computing'

I’ll be in Barcelona next week, for Mobile World Congress. I’m going to be based on Canonical’s stand. It’s been a few years since I went to this show, and it will be my first time in Barcelona. I’m looking forward to some new experiences.

I keep a USB stick with OSX installed on it, and today I got to test if I could use this to install a firmware update.

Short version: It just works. Slightly longer version: I just rebooted a few times, holding down alt/option whenever I needed to boot OSX from the USB stick. The OSX software updater took care of the rest.

(One of the nice things about my new job is working ‘in public’. I’m
tagging posts like these with ‘Canonical’, if you want to filter
them)

Hybris (aka libHybris) is a piece of enabling technology
that lets an OS distribution like Ubuntu use parts of Android software
in binary form, without needing a recompile of those binaries. Ubuntu
is using it for its ARM based Ubuntu Touch distributions, which re-use
the Android BSP for the underlying hardware platform.

libHybris is two things: A dynamic linker, which provides the
generic functionality, and then a set of wrapper libraries that
provide particular Android libraries to the other OS. Whilst the code
is clearly organised, it might be helpful to have a separate sample
which demonstrates how to use the core Hybris features. That is where
Bionic JPEG comes in.

Bionic is the name of Android’s C runtime library. On Ubuntu
the conventional C runtime is glibC. So another way of looking at
Hybris is to regard it as a way to use bionic based binaries in a
glibC based OS. Hence the name of this project.

Bionic JPEG aims to demonstrate how to call a library compiled for use
on Android (In this case the IJG JPEG library) from an Ubuntu
binary. To do this, I’ve divided the IJG code into its library and
client components, then compiled the library with the Android NDK, and
the client with the Ubuntu Touch toolchain. In order for the clients
to use the Android library, a small ‘bridge’ library that calls
libHybris glues the two together. By designing this bridge library to
present the same API as the IJG library, no changes are needed to any
of the IJG source code.

The core of Hybris is clearly derived from the Bionic source, and is a
port of the Android dynamic linker to Ubuntu. This knows how to load
an Android Elf32 binary into an Ubuntu process, which is a trick the
standard Ubuntu dynamic linker can’t do. From the look of the code,
Android can effectively link/prelink binaries in several ways, and it
is loading these binaries that is the key Hybris feature. In addition,
as it resolves symbols present in the binary it loads, it can hook
them to somewhere else. Hybris then uses this to hook all the bionic
entrypoints, and re-direct them to glibC. This isn’t always a simple
symbol substitution – there are differences between the C libraries
that means Hybris has some implementations within it, that then call
on to glibC.

Whilst the IJG code is unmodified, I have changed the name of the
library produced. It turned out that the Android images I was using
(derived from CyanogenMod 10.1 images for the Nexus 4) already have a
copy of libJPEG, from an earlier version of the IJG code. In order to
avoid a collision, Bionic JPEG names its library libjpeg2.

For more details, see the README in the source tarball (available in
the project downloads). Note that I don’t anticipate
Bionic JPEG demonstrates something commonly done by Ubuntu SDK
users. Over time (several release cycles), I think the Ubuntu
community hope to phase out our dependence on Android, in favour of
the common Linux upstreams Ubuntu and Android share. That will take
time, and need us to be successful enough for hardware manufacturers
to offer direct support. For now, using Android gets us that support
for the cost of maintaining Hybris.

That being said, even while libHybris exists, I don’t think it will be
a common thing for people to extend it: for most cases, the Android
libraries on a given device will already have a complete libHybris
bridge.

For the teams that need to maintain those Android parts, there may be
a need to extend libHybris, or even just to understand it a little
better. It is with that use case in mind that I created this example.

Last week, I attended Mobile Asia Expo (MAE) in Shanghai. It was my first experience of China, and I have to say I thoroughly enjoyed it. I got the chance to meet lots of folk from Canonical, as we all arrived from around the world to attend the trade show.

One of my tasks was to assist the London marketing team with loading the demo build we selected for showing off at the show. If you’d like to see it as well (what, you couldn’t fly to Shanghai to see it?), you can simply load it from our servers.

You’ll need a Nexus 4 or a Nexus 10 device, and you need to be prepared to replace the android software on it (you can go back). You need to setup the phablet-flash tool. The desktop setup part of our install instructions are sufficient, but the whole document is worth a read (this is still developer territory, and not quite for end users yet). Connect the device via it’s USB cable to your host Ubuntu desktop.

If your device has already been modified to run adb as root, the instructions are simple:

Now, boot to recovery mode (select it from the bootloader menu), which has a working adb.
We can push a zip to ‘/sdcard/autodeploy.zip’ and the recovery tool will flash it at next boot.
First, do the android BSP:

When the device has rebooted, and settles down to the charging icon, reboot it by hand to the recovery mode again, by booting to the bootloader and selecting recovery mode.
We can now flash Ubuntu onto it:

Now the device will boot into ubuntu, and you can add the demo content as before:

$ phablet-network-setup
$ phablet-demo-setup

If you have a Nexus 10, then substitute ‘manta’ where you see ‘mako’ above. Note that it needs both volume keys and the power button held down to get to the bootloader.

I found that sometimes this build would not populate the people lens correctly, or show the thumbnail pictures of contacts. I found that a reboot (after opening contacts in the phone app) worked to resolve it.

If you’re curious what changed to make these images ‘legacy’, it was the container switch, announced here.

Or two ways to install Ubuntu 13.04 on a ‘MacBook Pro, 13″ with Retina
display’ (also known as MacBookPro10,2)…

Having recently joined Canonical, my first task was to provision a
laptop to work on, naturally running Ubuntu. Asking for advice about
which models to choose, I was advised to seek out designs with Intel
wifi & graphics adaptors, presumably down to the quality of the open
source drivers available. The 13″ retina MacBook has a screen I wanted
to use, and met half the criteria – it uses Intel graphics. I was also
encouraged to believe that installing on a modern Mac had gotten a lot
easier than the information readily available suggests, so I gambled
on the wifi requirement. It seems to have paid off.

The major decision is how to host OS X. You need to maintain a copy to
host the firmware updates occasionally issued by Apple – they make no
pretense to support anything other than OS X as a host for these.

You can elect to have OS X on an external drive, or keep an internal
partition with it on. The first implies that when the external drive is
not connected, the PC will be ‘single booting’ to Ubuntu, and the
internal storage can be entirely managed by Ubuntu. The second option
implies a ‘dual boot’ setup, and dividing the internal storage between
the two operating systems. Having chosen a single boot or dual boot configuration, a
secondary decision is how to select between this OS X instance and
Ubuntu at boot time. The Mac’s boot manager ‘Startup Manager‘ can
easily cope with multiple boot options, but it does prefer to manage
instances of OS X. I only enjoy using it when it can be used as with
OS X, booting straight to some preferred default unless keys are held
down. rEFInd is an excellent alternative boot manager, and I’ve used
it in the dual boot configuration.

Elect to ‘continue’ after selecting your language. You’ll have been informed you’re currently offline by a notification window.

Elect to ‘Install this third party software’ and continue. This is where your wifi driver is coming from.

Elect to set up the ‘Broadcom Corporation BCM4331 802.11a/b/g/n’, selecting ‘connect to this network’, and configuring your wifi details. ‘Connect’ attempts to connect, and you use the same button a second time (as ‘continue’) to proceed if the connection works.

Once you’ve first logged in, allow Ubuntu to pull down the updates since the CD image you used was mastered.

After it reboots, and you log in, you may find your audio is mute. In which case, you’ve been bitten by bug 1169984, and you need to follow the workaround listed. When I wrote these notes the fix hadn’t made it to the auto-update set.

You will find the built in microphone doesn’t work. To enable this, the snd_hda_intel module needs to be explicitly informed which model it is running on, so add:options snd-hda-intel model=mbp101
to the file /etc/modprobe.d/alsa-base.conf (sudo nano /etc/modprobe.d/alsa-base.conf is a good choice, if you’re used to mac editors), and reboot one last time.

The basic steps

Boot OS X and get the latest updates. Adjust the volume if you want to mute the boot chime

Restart, and ask the Mac to boot its recovery partition. (Hold down ‘option/alt’ while it boots)

Install a copy of OS X on your external drive

Install Ubuntu, replacing the internal OS X, using the 3rd party software offered (that’s where the wifi drivers are)

Fix up the Ubuntu EFI install, so the Mac Startup Manager can understand it

Fix a couple of audio bugs

Whenever you want to boot to OS X you need to insert your usb key, and use ‘option/alt’ during boot to select it.

More detailed steps

Boot the Macintosh, and walk through the OS X setup

Now’s a good time to adjust the volume. If you mute now, the boot
chime will also be muted – Ubuntu lacks a tool to control the boot chime.

Allow OS X to update (via the App Store). This may take a few cycles, if several updates need applying in sequence, and it will catch any firmware updates already issued.

Restart, holding down ‘option/alt’ (the label depends on your keyboard) as the boot starts, to get the Apple Startup Manager. Select the Recovery partition, and boot that.

Insert your external drive, and if needed, use Disk Utility to arrange for it to have a single ‘Mac OS Extended (Journaled)’ partition with the device using a ‘GUID Partition Table’ (This part is in Options). Note that the utility will allow space for a recovery partition also. Quit to return to the recovery menu.

‘Reinstall OS X’, selecting your external drive as the target. The setup wizard can be configured as you wish, and it appears that an Apple ID is optional to set up the OS, and receive firmware and OS updates.

Boot this version of the OS, and take the chance to make sure it is up to date. Shut it down, and remove the external drive.

Insert your Ubuntu USB key (use a 64-bit, not 64-bit Mac image, see notes below), and boot to the Startup Manager using ‘option/alt’. Select one of the ‘EFI Boot’ options (both seem to work equally well).

Select ‘Install Ubuntu’

Elect to ‘continue’ after selecting your language. You’ll have been informed you’re currently offline by a notification window.

Elect to ‘Install this third party software’ and continue. This is where your wifi driver is coming from.

Elect to set up the ‘Broadcom Corporation BCM4331 802.11a/b/g/n’, selecting ‘connect to this network’, and configuring your wifi details. ‘Connect’ attempts to connect, and you use the same button a second time (as ‘continue’) to proceed if the connection works.

Elect to ‘Replace Mac OS X with Ubuntu’. Given that we’re effectively taking over the machine, the wizard knows how to offer full disk encryption and LVM support. Use them if you wish, and enter the necessary encryption key if you do.

Check the final dialog is proposing to install on the internal disk, and then start the install proper.

The Startup Manager thinks a bit, and then gives up, prompting you with a Folder icon with a question mark. Insert the Ubuntu USB key, and after booting it, elect to ‘Try Ubuntu without installing’. We’ll use Ubuntu to patch things up with Startup Manager.

Bring up a terminal, mount your EFI partition (a relatively small FAT32 partition), and rename the bootloader ubuntu installed to have the default EFI name:$ sudo mkdir /boot/efi
$ sudo mount /dev/sda1 /boot/efi
$ sudo mv /boot/efi/EFI/ubuntu /boot/efi/EFI/BOOT
$ sudo mv /boot/efi/EFI/BOOT/grubx64.efi /boot/efi/EFI/BOOT/BOOTX64.EFI
You can now shutdown Ubuntu and remove the USB key. There may be other more sophisticated ways to patch up what Ubuntu and Startup Manager can agree via the dialect of EFI they have in common, but setting the bootloader name to the default works for now.

Boot the machine, and it will take you straight to Ubuntu.

Once you’ve first logged in, allow Ubuntu to pull down the updates since the CD image you used was mastered.

After it reboots, and you log in, you may find your audio is mute. In which case, you’ve been bitten by bug 1169984, and you need to follow the workaround listed. When I wrote these notes the fix hadn’t made it to the auto-update set.

You will find the built in microphone doesn’t work. To enable this, the snd_hda_intel module needs to be explicitly informed which model it is running on, so add:options snd-hda-intel model=mbp101
to the file /etc/modprobe.d/alsa-base.conf (sudo nano /etc/modprobe.d/alsa-base.conf is a good choice, if you’re used to mac editors), and reboot one last time.

You’re done!

Notes

If you’ve got one, the Thunderbolt ethernet adaptor works, and removes the need to install 3rd party software at install time to get on the internet. I assume you could then choose exactly which third party software you install post-setup, and get the wifi that way.

As far as what works, the screen is gorgeous, but I think it’s worth tweaking font sizes and so on to trade readability & screen real estate (Unity Tweak Tool is your friend). I like that Ubuntu gives me more choices here than OS X. The ‘function’ keys above the keyboard work similarly to OS X, with all but the launchpad (!) and mission control buttons mapping to Ubuntu functions. The keyboard & screen backlights work, as do the audio controls. The trackpad can be configured to support two finger scrolling in the same fashion as OS X, if you’re like me and already habituated to that.

It appears that an Apple ID is optional during setup of your OS X image, and the App Store still provides OS and firmware updates to machines without a logged in ID.

FWIW, I can see no reason you couldn’t configure a dual boot system to encrypt the Ubuntu installation, but the wizard can’t help you, and I’ve not explored the options (my machine single boots).

If you’re willing to live without OS X entirely you have two recovery options if you want to uninstall Ubuntu and return to OS X. You can create a standalone recovery USB key (needs less space than an OS X bootable disk), or you can depend on the internet recovery mode available in the Apple Startup Manager.

Ubuntu 13.04 is available in at least 3 desktop flavors: 32bit, 64bit, and ’64bit Mac’. Whilst the 32bit one clearly can work (I tried it, the OS did boot), you end up using a BIOS compatibility shim that Apple seem to have only intended for use with Windows. Having used the plain 64 bit install a lot while writing this, I did briefly try the mac flavour. My notes are poor, but I recall it didn’t work well on this modern Mac. Given the current support in the standard 64 bit installer, there seems to be no need to use it. Fortunately the default download page contains apparently good advice to select the standard 64 bit verson for a modern PC.

The built in microphone not working had me puzzled for a while, and I used a USB headset until I found the workaround. I was looking for information on hotplugging thunderbolt (which seems not to work yet), and found an installation guide for Fedora 18 that noted the crucial step of letting snd_hda_intel know it is running on an mpb101. With this step the built in audio is fully functional.